U.S. patent application number 13/306808 was filed with the patent office on 2012-05-31 for wind power generation systems including segmented stators.
This patent application is currently assigned to General Electric Company. Invention is credited to Kiruba Sivasubramaniam Haran, Randy Scott Longtin, Robert Michael Zirin.
Application Number | 20120133145 13/306808 |
Document ID | / |
Family ID | 46126097 |
Filed Date | 2012-05-31 |
United States Patent
Application |
20120133145 |
Kind Code |
A1 |
Longtin; Randy Scott ; et
al. |
May 31, 2012 |
WIND POWER GENERATION SYSTEMS INCLUDING SEGMENTED STATORS
Abstract
The present disclosure relates to wind power generation systems
having a segmented stator with a structural element and a plurality
of coils. The wind power generation systems also include a rotor
adapted to be rotated by wind to induce current in the plurality of
coils and a lamination stack having a plurality of lamination
plates disposed about the plurality of coils and a dovetail recess
formed in the lamination stack. The wind power generation systems
also include a dovetail bar adapted to be received by the dovetail
recess and adjusted by a bolt to engage the lamination stack and
the structural element of the segmented stator to form a torque
transfer interface. Torque is adapted to be transferred from the
lamination stack to the segmented stator via friction at the
interface.
Inventors: |
Longtin; Randy Scott;
(Schenectady, NY) ; Zirin; Robert Michael;
(Niskayuna, NY) ; Haran; Kiruba Sivasubramaniam;
(Clifton Park, NY) |
Assignee: |
General Electric Company
Schenectady
NY
|
Family ID: |
46126097 |
Appl. No.: |
13/306808 |
Filed: |
November 29, 2011 |
Current U.S.
Class: |
290/55 |
Current CPC
Class: |
Y02E 10/72 20130101;
H02K 1/146 20130101; Y02E 10/725 20130101; H02K 2213/12 20130101;
H02K 1/185 20130101; H02K 7/1838 20130101 |
Class at
Publication: |
290/55 |
International
Class: |
F03D 9/00 20060101
F03D009/00 |
Claims
1. A wind power generation system, comprising: a segmented stator
comprising a structural element and a plurality of coils; a rotor
configured to be rotated by wind to induce current in the plurality
of coils; a lamination stack comprising a plurality of lamination
plates disposed about the plurality of coils and a dovetail recess
formed in the lamination stack; and a dovetail bar configured to be
received by the dovetail recess and adjusted by an adjustment
mechanism to engage the lamination stack and the structural element
of the segmented stator to form a torque transfer interface,
wherein torque is configured to be transferred from the lamination
stack to the segmented stator via friction at the interface.
2. The system of claim 1, wherein the dovetail bar comprises a
multi-pieced assembly.
3. The system of claim 2, wherein the multi-pieced assembly
comprises an extension extending from a dovetail shaped base, and
the adjustment mechanism comprises a bolt that is configured to be
received by the extension.
4. The system of claim 3, wherein when the lamination stack and the
structural element are engaged, an annular airgap is established
between the extension of the dovetail bar and the structural
element.
5. The system of claim 4, wherein an interference fit is configured
to be established between a surface of the extension of the
dovetail bar and the structural element to substantially close the
annular airgap during the occurrence of a slippage event.
6. The system of claim 1, wherein the structural element of the
segmented stator comprises a substantially continuous
superstructure.
7. The system of claim 1, wherein each segment of the segmented
stator comprises a portion of the structural element, and wherein
each portion of the structural element is configured to be bolted
to another portion of the structural element to form the structural
element.
8. The system of claim 1, comprising a plurality of tension rods
disposed throughout the lamination stack and configured to maintain
engagement between the plurality of lamination plates.
9. A wind power generation system, comprising: a lamination stack
comprising a plurality of lamination plates, wherein the lamination
stack is segmented into a first segment having a first portion of a
male dovetail on an end of the first segment and a second segment
having a second portion of the male dovetail on an end of the
second segment; and a clamp comprising a first clamp portion having
a portion of a female dovetail recess configured to receive the
first portion of the male dovetail and a second clamp portion
having a portion of the female dovetail recess configured to
receive the second portion of the male dovetail; and a securement
member configured to couple the first clamp portion with the second
clamp portion to maintain the first segment of the lamination stack
and the second segment of the lamination stack in a substantially
fixed relationship with respect to one another.
10. The system of claim 9, wherein the securement member comprises
a bolt configured to be tightened to clamp the first clamp portion
and the second clamp portion about the first portion of the male
dovetail and the second portion of the male dovetail.
11. The system of claim 9, comprising a spacer configured for
placement between a first assembly comprising the first clamp
portion and the first portion of the male dovetail and a second
assembly comprising the second clamp portion and the second portion
of the male dovetail.
12. The system of claim 11, wherein the spacer comprises a
plurality of apertures configured to receive a plurality of bolts
configured to tighten to secure the first segment and the second
segment of the lamination stack together.
13. The system of claim 9, wherein the lamination stack is disposed
about a plurality of magnetic coils.
14. The system of claim 13, comprising a rotor configured to be
rotated by wind to induce current in the plurality of magnetic
coils.
15. The system of claim 14, comprising a generator configured to
utilize the induced current to produce power.
16. The system of claim 9, wherein the lamination stack is
configured to be coupled to a stationary superstructure.
17. The system of claim 9, wherein the first portion of the male
dovetail comprises a series of substantially similar male dovetail
portions disposed on respective ends of each of the plurality of
lamination plates, and wherein the second portion of the male
dovetail comprises a series of substantially similar male dovetail
portions disposed on respective ends of each of the plurality of
lamination plates.
18. A wind power generation system, comprising: a lamination stack
comprising a plurality of lamination plates, wherein the lamination
stack is segmented into a first segment and a second segment; a
first c-channel structure disposed on a first end of the first
segment; a second c-channel structure disposed on a second end of
the first segment, wherein the c-channel of the first c-channel
structure and the c-channel of the second c-channel structure are
disposed opposite one another along the first segment; a third
c-channel structure disposed on a first end of the second segment;
and a fourth c-channel structure disposed on a second end of the
second segment, wherein the c-channel of the third c-channel
structure and the c-channel of the fourth c-channel structure are
disposed opposite one another along the first segment; and a
securement member configured to couple pairs of the first c-channel
structure, the second c-channel structure, the third c-channel
structure, and the fourth c-channel structure to maintain the first
segment of the lamination stack and the second segment of the
lamination stack in a substantially fixed relationship with respect
to one another.
19. The system of claim 18, wherein the securement member comprises
one or more bolts configured to be received through each coupled
pair of c-channel structures.
20. The system of claim 18, wherein the first c-channel structure
is welded to the first end of the first segment, the second
c-channel structure is welded to the second end of the first
segment, the third c-channel structure is welded to the first end
of the second segment, and the fourth c-channel structure is welded
to the second end of the second structure.
Description
BACKGROUND
[0001] Wind turbines typically include multiple blades extending
from a central hub. The hub is rotatably coupled to a nacelle
suspended above the ground by a tower. Generally, the nacelle
houses an electric generator coupled to the hub and configured to
generate electrical power as the blades are driven to rotate by the
wind. Wind turbine blades are typically designed and manufactured
to efficiently transfer wind energy into rotational motion, thereby
providing the generator with sufficient rotational energy for power
generation. Wind power plants typically consist of multiple wind
turbines of this type spread over a given geographic region. Wind
passing over the region causes blades associated with each wind
turbine to rotate, thereby generating electrical power.
[0002] Each wind turbine typically includes a variety of components
that cooperate to translate the wind energy into electrical power.
Typical wind turbines include a stationary stator having magnetic
coils and a rotating rotor that induces current in the magnetic
coils. In some systems, in order to generate the desired electrical
power output, the stator may be dimensioned such that transport of
the stator in its fully assembled form is impractical. Accordingly,
in certain instances, it may be necessary to segment and
disassemble the stator for transport and to reassemble the stator
in the desired use location. Unfortunately, once assembled, the
segmented stator may experience significant decreases in structural
integrity due to the occurrence of undesirable radial deflections
at the locations where the segments are joined. Accordingly, there
exists a need for improved segmented stators that overcome this
drawback.
BRIEF DESCRIPTION
[0003] In a first embodiment, a wind power generation system
includes a segmented stator with a structural element and a
plurality of coils. The wind power generation system also includes
a rotor adapted to be rotated by wind to induce current in the
plurality of coils and a lamination stack having a plurality of
lamination plates disposed about the plurality of coils and a
dovetail recess formed in the lamination stack. The wind power
generation system also includes a dovetail bar adapted to be
received by the dovetail recess and adjusted by a bolt to engage
the lamination stack and the structural element of the segmented
stator to form a torque transfer interface. Torque is adapted to be
transferred from the lamination stack to the segmented stator via
friction at the interface.
[0004] In a second embodiment, a wind power generation system
includes a lamination stack having a plurality of lamination
plates. The lamination stack is segmented into a first segment
having a first portion of a male dovetail on an end of the first
segment and a second segment having a second portion of the male
dovetail on an end of the second segment. The wind power generation
system also includes a clamp having a first clamp portion having a
portion of a female dovetail recess adapted to receive the first
portion of the male dovetail and a second clamp portion having a
portion of the female dovetail recess adapted to receive the second
portion of the male dovetail. The wind power generation system
further includes a securement member adapted to couple the first
clamp portion with the second clamp portion to maintain the first
segment of the lamination stack and the second segment of the
lamination stack in a substantially fixed relationship with respect
to one another.
[0005] In a third embodiment a wind power generation system
includes a lamination stack having a plurality of lamination plates
and being segmented into a first segment and a second segment. The
system also includes a first c-channel structure disposed on a
first end of the first segment and a second c-channel structure
disposed on a second end of the first segment, wherein the
c-channel of the first c-channel structure and the c-channel of the
second c-channel structure are disposed opposite one another along
the first segment. The system also includes a third c-channel
structure disposed on a first end of the second segment and a
fourth c-channel structure disposed on a second end of the second
segment, wherein the c-channel of the third c-channel structure and
the c-channel of the fourth c-channel structure are disposed
opposite one another along the first segment. Further, a securement
member is adapted to couple pairs of the first c-channel structure,
the second c-channel structure, the third c-channel structure, and
the fourth c-channel structure to maintain the first segment of the
lamination stack and the second segment of the lamination stack in
a substantially fixed relationship with respect to one another.
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] These and other features, aspects, and advantages of the
present invention will become better understood when the following
detailed description is read with reference to the accompanying
drawings in which like characters represent like parts throughout
the drawings, wherein:
[0007] FIG. 1 is a front view of a wind turbine system for use in a
wind power plant in accordance with aspects of the present
disclosure;
[0008] FIG. 2 is a schematic diagram of multiple wind turbine
systems, as shown in FIG. 1, provided as part of a wind power
plant, in accordance with aspects of the present disclosure;
[0009] FIG. 3 is a perspective view of an embodiment of a segmented
stator having a pipe superstructure coupled to a lamination stack
and adapted for use in a wind turbine;
[0010] FIG. 4 illustrates segments of a lamination stack coupled
together with a clamped dovetail assembly in accordance with an
embodiment;
[0011] FIG. 5 illustrates a spacer that may be included in an
embodiment of the clamped dovetail assembly of FIG. 4;
[0012] FIG. 6 illustrates a clamped dovetail assembly disposed on a
portion of a lamination stack in accordance with an embodiment;
[0013] FIG. 7 illustrates segments of a lamination stack coupled
together with a c-channel assembly in accordance with an
embodiment;
[0014] FIG. 8 illustrates a stator superstructure and a lamination
stack coupled together with a dovetail assembly in accordance with
an embodiment; and
[0015] FIG. 9 illustrates a stator superstructure and a lamination
stack coupled together with a dovetail assembly in accordance with
an embodiment.
DETAILED DESCRIPTION
[0016] One or more specific embodiments will be described below. In
an effort to provide a concise description of these embodiments,
all features of an actual implementation may not be described in
the specification. It should be appreciated that in the development
of any such actual implementation, as in any engineering or design
project, numerous implementation-specific decisions must be made to
achieve the developers' specific goals, such as compliance with
system-related and business-related constraints, which may vary
from one implementation to another. Moreover, it should be
appreciated that such a development effort might be complex and
time consuming, but would nevertheless be a routine undertaking of
design, fabrication, and manufacture for those of ordinary skill
having the benefit of this disclosure.
[0017] When introducing elements of various embodiments disclosed
herein, the articles "a," "an," "the," and "said" are intended to
mean that there are one or more of the elements. The terms
"comprising," "including," and "having" are intended to be
inclusive and mean that there may be additional elements other than
the listed elements.
[0018] As described in detail below, provided herein are
embodiments of segmented stators for use in wind power generation
systems. A variety of coupling mechanisms may be utilized to couple
segments of the segmented stators with one another. For example, in
some embodiments, a dovetail bar adjustable within a dovetail
recess may be utilized to secure a first portion of a lamination
stack to a second portion of a lamination stack to maintain the
first portion and the second portion in a substantially fixed
relationship with respect to one another. For further example, in
another embodiment, the portions of the lamination stack may each
have a portion of a male dovetail, and a two-piece clamp having a
dovetail recess may be secured about the male dovetail of the
lamination stack with a securement member. Each of these coupling
mechanisms may be utilized to connect portions of the segmented
stator together such that during rotation of the rotor, the
structural integrity (e.g. radial deflections, stresses, vibration
response) of the stator is maintained, particularly at the
connection points between segments of the segmented stator. The
foregoing feature may offer distinct advantages over traditional
systems, for example, in instances in which the stator segments are
assembled at the point of use instead of being assembled prior to
shipping.
[0019] Turning now to the drawings, FIG. 1 is a front view of a
wind turbine system 10 capable of converting wind energy into
electrical energy. The wind turbine system 10 includes a tower 12,
a nacelle 14, and blades 16. The blades 16 are coupled to a
generator 18 within the nacelle 14 by a hub 20 that rotates with
the blades 16. The blades 16 are capable of converting the linear
air flow from the wind into rotational motion. As the blades 16
rotate, the coupling between the hub 20 and the generator 18 within
the nacelle 14 drives components of the generator 18 to rotate,
thereby producing electrical energy. While three blades 16 are
included in the wind turbine system 10 of the present embodiment,
alternative embodiments may include more or fewer blades 16.
[0020] Each blade 16 includes a leading edge 22 and a trailing edge
24. The air flow engages the leading edge 22 and flows toward the
trailing edge 24. Due to the shape of the blades 16, aerodynamic
forces caused by the air flow induce the blades 16 to rotate,
thereby driving the generator 18 to produce electrical power.
Efficiency of the wind turbine system 10 is at least partially
dependent upon converting linear air flow into rotational energy.
Therefore, the blades 16 are generally configured to efficiently
transfer wind energy into rotational motion. For example, blade
shape may be selected to enhance air flow over the blade 16 such
that aerodynamic forces induce the blade 16 to rotate. In addition,
the blades 16 are typically manufactured to be substantially
smooth, such that air flows over the blades 16 without
interference.
[0021] With the foregoing discussion of a wind turbine system 10 in
mind, FIG. 2 is a schematic diagram of a multitude of such wind
turbine systems 10 disposed to function together as part of a wind
power generation system, such as wind power plant 40. Electrical
currents produced by the wind turbine systems 10 of the wind power
plant 40 are provided to an electrical power grid 42, thereby
providing electrical energy to consumers connected to the grid 42.
Further one or more controllers 44 may be provided to control
and/or monitor operation of the wind power plant 40. Such
controllers 44 may be provided as general or special purpose
computers (or other suitable processor-based systems) configured to
execute code or routines that allow monitoring and/or control of
the wind power plant 40 as a whole and/or of individual wind
turbine systems 10 of the plant 40.
[0022] FIG. 3 is a perspective view of an embodiment of a segmented
stator 46 suitable for use in the wind turbine system 10. The
segmented stator 46 includes a first segment 48 and a second
segment 50. As illustrated, each of the segments 48 and 50 include
portions of the stator structures, which are segmented to
facilitate shipping and subsequently assembled at the point of use.
For example, in the depicted embodiment, the stator 46 includes a
segmented end plate 52, a superstructure 54, and a segmented
lamination stack 56 formed from a variety of axially stacked
plates. The superstructure 54 includes a plurality of pipes 58
having dovetail bars 59 coupled thereto (e.g., via welding) in the
illustrated embodiment, although the superstructure 54 may be any
suitable structural element in other embodiments. Further, although
the illustrated segmented stator 46 includes two segments 48 and
50, other embodiments may include any desired quantity of segments,
depending on implementation-specific parameters, such as the
desired capacity of the wind turbine system 10, which may dictate
the overall size and/or angular average of the segmented stator 46.
Additionally, although only half of the stator 46 is illustrated,
one skilled in the art would understand that a full stator may be
assembled before use.
[0023] As illustrated, when the first segment 48 and the second
segment 50 are coupled together, an interface 60 is established
between adjacent segments, and a clamping mechanism 62 may be
utilized to couple an end portion 64 of the first segment 48 to an
end portion 66 of the second segment 50. In certain embodiments, an
air gap may be present at the interface 60, and the size of the air
gap may vary based on tolerances present in the manufacture of each
of the segments 48 and 50. The clamping mechanism 62 may be
sufficiently adjustable to overcome the drawbacks associated with a
variable air gap and maintain the first segment 48 in a
substantially fixed position relative to the second segment 50
during operation of the segmented stator 46.
[0024] FIG. 4 illustrates an embodiment of the clamping mechanism
62 that may be utilized to couple a first portion 68 of the
segmented lamination stack 56 and a second portion 70 of the
segmented lamination stack. In this embodiment, the clamping
mechanism 62 includes a clamp 72 having a first clamp portion 74
and a second clamp portion 76. The first clamp portion 74 includes
a first portion of a female dovetail recess 78, and the second
clamp portion 76 includes a second portion of the female dovetail
recess 80. The clamping mechanism 62 also includes a securement
member 82, such as bolt 84, capable of securing the first clamp
portion 74 and the second clamp portion 76 together. Further, in
this embodiment, a first portion of a male dovetail 86 is disposed
on a first end 88 of the first segment 68 of the segmented
lamination stack 56, and a second portion of the male dovetail 90
is disposed on a second end 92 of the second segment 70 of the
segmented lamination stack 56.
[0025] During assembly, the female dovetail recess 78 of the first
clamp portion 74 receives the male dovetail portion 86 disposed on
the first lamination stack segment 68, and the second clamp portion
76 receives the male dovetail portion 90 disposed on the second
lamination stack segment 70. Subsequently, as the bolt 84 is
tightened, the male dovetail portions 86 and 90 contact the female
dovetail recess portions 78 and 80, and the first clamp portion 74
and the second clamp portion 76 are clamped together, thus reducing
the air gap between the lamination stack segments 68 and 70. The
securement mechanism 82 may be adjusted depending on the size of
the air gap that arises when the first segment 68 and the second
segment 70 of the lamination stack 56 are positioned next to one
another. Nevertheless, once the clamping mechanism 62 is adjusted
to clamp the segments 68 and 70 of the lamination stack 56
together, an air gap between the lamination stack 56 and the rotor
of the wind turbine may be maintained at a substantially constant
value since the peak radial deformation at the interface 60 is
substantially reduced via inclusion of the clamping mechanism
62.
[0026] In the illustrated embodiment, the securement mechanism 82
includes the bolt 84, but it should be noted that in other
embodiments, the securement mechanism 82 may include a plurality of
bolts or other adjustment devices capable of assembling the first
clamp portion 74 and the second clamp portion 76 together.
Additionally, although the male dovetail portions 86 and 90 are
illustrated as single structures coupled to the end portions 88 and
92 of the segments 68 and 70, in some embodiments, the male
dovetail portions 86 and 90 may each include a series of
substantially similar dovetail portions, each disposed on a
separate plate of the lamination stack 56.
[0027] FIG. 5 illustrates a spacer 94 that may be included in the
clamping mechanism 62 of FIG. 4 in embodiments in which it is
desired to reduce the air gap between the segments 68 and 70 of the
lamination stack before being clamped by the clamping mechanism 62.
In the illustrated embodiment, the spacer 94 includes apertures 96
dimensioned to receive bolts 84 and capable of preventing or
eliminating the likelihood of misalignment of the spacer 94 within
the clamping assembly 62. In embodiments in which the clamping
mechanism includes the spacer 94, the spacer 94 is inserted into
the air gap between a first side including the first clamp portion
74 and the first dovetail portion 86 and a second side including
the second clamp portion 76 and the second dovetail portion 90.
During operation of the wind turbine, the spacer 94 may facilitate
transfer of compressive loads between components of the stator
assembly.
[0028] FIG. 6 illustrates the clamping mechanism 62 located on
alternate portions of the ends 88 and 92 of the segments 68 and 70
of the segmented lamination stack 56. Specifically, in this
embodiment, a first clamping mechanism 62 is located on the first
end 88 of the first segment 68, and a second clamping mechanism 62
substantially similar to the first clamping mechanism is located on
the end portion 92 of the segment 70. As such, in this embodiment,
the clamping mechanism is not located at the interface 60 between
the segments 68 and 70, but rather, the mechanism is located
entirely on one segment or the other. The foregoing feature may
provide stiffness to the ends 88 and 92 of the segments 68 and 70,
thus possibly reducing radial deflections, which may be due to
electromagnetic forces, at the cantilevered ends between 59 and 60
of each stator segment.
[0029] FIG. 7 illustrates an alternate embodiment of the clamping
mechanism 62 that clamps the end portion 88 of the first segment 68
of the lamination stack 56 to the end portion 92 of the second
segment 70 of the lamination stack 56. In this embodiment, the
clamping mechanism 62 includes a first c-channel structure 98 and a
second c-channel structure 100. Although, only the first side of
the segmented lamination stack 56 is shown in FIG. 7, as would be
understood by one skilled in the art, a third c-channel structure
and a fourth c-channel structure may similarly couple the
non-illustrated ends of the segments 68 and 70. In the depicted
embodiment, the first c-channel structure 98 includes a first
c-channel 102, and the second c-channel structure 100 includes a
second c-channel 104. As shown, the first c-channel 102 and the
second c-channel 104 are disposed opposite one another during use.
Further, a securement mechanism 106 having one or more bolts 108
tightens to couple the c-channel structures 98 and 100
together.
[0030] In certain embodiments, the first c-channel structure 98 and
the second c-channel structure 100 are secured to the ends 88 and
92 of the segments 68 and 70 of the segmented lamination stack 56
via welding. However, it should be noted that the c-channels 98 and
100 may be coupled to the lamination stack segments 68 and 70 in a
variety of suitable ways before or after the manufacture of the
lamination stack 56. Additionally, as in previous embodiments, a
spacer, such as spacer 94 of FIG. 5, may be placed in an air gap
between the c-channels 98 and 100 before bolting.
[0031] FIG. 8 illustrates an embodiment of a dovetail assembly 110
that may be utilized to secure the lamination stack 56, which may
be segmented or non-segmented, to a structural element 112 of the
stator. In this embodiment, the structural element 112 may be a
stator superstructure formed as a barrel structure, while in other
embodiments, the structural element may be any element of the
stator that remains substantially stationary as the rotor of the
wind turbine rotates. The illustrated embodiment of the dovetail
assembly 110 includes a dovetail bar 114, a dovetail recess 116,
and one or more bolts 118, which may be spaced axially and/or
circumferentially. However, the dovetail assembly 110 is subject to
considerable implementation-specific variations. For example, in
one embodiment, the bolt 118 may be replaced by another securement
device.
[0032] During use, the bolt 118 is screwed into the dovetail bar
114, and the dovetail bar 114 tightens, thus engaging the
structural element 112 with the lamination stack 56 at a torque
transfer interface 120. Accordingly, as the rotor of the wind
turbine assembly is rotated by wind and current is induced in coils
of the stator, torque is transferred due to tangential
electromagnetic forces via the torque transfer interface 120 from
the lamination stack 56 to the structural element 112 via friction
at the interface 120. The foregoing feature as well as other
features of presently disclosed embodiments may enable the bolts
118 to carry shear and tension loads while substantially reducing
or eliminating the possibility of the bolts 118 carrying bending
loads if slippage occurs (e.g. a short circuit event in which
torque loads spike above normal) at interface 120 during operation
of the rotor. For example, by providing an air gap 122 between the
dovetail bar 114 and the structural element 112, the bending load
on the bolt 118 may be designed such that it does not exceed the
bolt's proof strength before contact occurs between 122 and 112.
Once the air gap 122 is closed and the structural element 112
contacts the dovetail 114 at surface 113, excess load is
transferred through this new contact interface while reducing or
eliminating the possibility of yielding/failure of the bolt 118 or
dovetail nut 114. In such cases, an interference fit may be
established between the surface 113 of the dovetail bar 114 and the
structural element 112.
[0033] During operation, in some embodiments, the adjustability of
the dovetail assembly 110 may ensure that the laminations remain
substantially engaged with the structural element 112 of the
stator. For example, in embodiments in which bolts are screwed into
the dovetail bars, the bolts may be adjusted to reduce or eliminate
air gaps between the dovetail pressure planes and the laminations.
The foregoing features may offer advantages over traditional
designs that may inadequately attempt to fix the lamination stack
to the stator.
[0034] FIG. 9 illustrates an alternate embodiment of the structural
element 112 being coupled to the lamination stack 56 via the
dovetail assembly 110 and a second assembly 124. In certain
embodiments, the assembly 124 may be dimensioned differently than
the dimensions of assembly 110. For example, in the illustrated
embodiment, the bolts of assembly 124 may be longer than the bolts
of assembly 110, but the width of the dovetail nut may be smaller.
In this embodiment, the structural element 112 is a substantially
continuous superstructure 126. That is, the structural element 112
is substantially continuous throughout each segment of the
segmented stator; the structural element 112 is not an array of
substantially similar elements, such as barrels or pipes, as in
previous embodiments. In one embodiment, the substantially
continuous superstructure is a shell, as shown in FIG. 9. However,
it should be noted that although only one segment is illustrated,
when assembled, additional segments may be connected to the
illustrated segment, for example, via insertion of bolts or other
securement devices through apertures 128 and corresponding
apertures in an adjacent segment. In this way, the ends of adjacent
segments may be secured in a substantially fixed position relative
to one another.
[0035] Further, the illustrated lamination stack 56 includes a
plurality of tension rods 130 capable of lamination compressive
preload of stack 56 throughout use. The dovetail assemblies 110 and
124 couple the lamination stack 56 to the structural element 112 of
the stator. More specifically, during operation, the dovetail
assembly 110 may be adjusted, as described in detail above with
respect to FIG. 8, to bring together the structural element 112 and
the lamination stack 56 at the interface 120. That is, as a bolts
or other securement devices are tightened through apertures 132 in
the structural element, the dovetail bar 114 is tightened, and
engagement is established between the laminations of the lamination
stack 56 and the structural element 112.
[0036] Still further, in the illustrated embodiment, the
multi-piece dovetail assembly 124 is capable of tightening to
couple an end portion 136 of the substantially continuous
superstructure 126 to an end portion 138 of the lamination stack
138. In this way, the ends 136 and 138 of the superstructure 126
and the lamination stack 56 may be secured to one another to
substantially reduce or elimination the inward radial deflection of
the cantilevered end (e.g., the free end) of the lamination stack
56 when loaded. In the illustrated embodiment, the multi-piece
dovetail assembly 124 includes a dovetail bar 140 and a dovetail
recess 142 dimensioned to receive the dovetail bar 140. However, in
other embodiments, the multi-piece dovetail assembly may include a
variety of other suitable pieces, such as one or more securement
mechanisms. For example, the dovetail bar 140 may be a two-piece
assembly including a first male dovetail portion and a second male
dovetail portion, each configured to be engaged by a securement
mechanism, such as a bolt during tightening.
[0037] This written description uses examples to disclose the
invention, including the best mode, and also to enable any person
skilled in the art to practice the invention, including making and
using any devices or systems and performing any incorporated
methods. The patentable scope of the invention is defined by the
claims, and may include other examples that occur to those skilled
in the art. Such other examples are intended to be within the scope
of the claims if they have structural elements that do not differ
from the literal language of the claims, or if they include
equivalent structural elements with insubstantial differences from
the literal languages of the claims.
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